DNS troubleshooting in PowerShell

 

DNS troubleshooting in PowerShell

DNS means domain name server or system you can say that so with the help of DNS in your system whenever you will browse anything like google.com so it will resolver by dns first. It is used for translates human-readable web addresses (like google.com) into computer-readable IP addresses. Anyone around the world can use it as a free alternative to their internet service provider's default DNS server.

The IP address 8.8.8.8 is a public Google Public DNS resolver operated by Google LLC.

DNS troubleshooting with PowerShell

1. Check which DNS server your computer is using

• Get-DnsClientServerAddress

This shows the DNS servers configured on each network adapter.


For example:

  
InterfaceAlias   ServerAddresses
--------------   ---------------
Wi-Fi            {192.168.1.1}
  

If you're on an AD lab, you would typically expect the client/member server to use the Domain Controller's IP as its DNS server.

2. Check DNS configuration for a specific adapter

• Get-DnsClientServerAddress -InterfaceAlias "Wi-Fi"

For Ethernet:

• Get-DnsClientServerAddress -InterfaceAlias "Ethernet"

 

3. Test whether DNS can resolve a hostname

This is one of the most useful commands for IT Support:

• Resolve-DnsName google.com

You should get information such as:


Name        Type   IPAddress
----        ----   ---------
google.com  A      xxx.xxx.xxx.xxx



For your AD lab, test your domain:

• Resolve-DnsName test.com

or your Domain Controller:

• Resolve-DnsName dc01.test.com

4. Test DNS using a specific DNS server

This is very useful for troubleshooting.

• Resolve-DnsName google.com -Server 8.8.8.8

You're saying:

• "Ask DNS server 8.8.8.8 to resolve this name."

You can compare it with your configured DNS server:

• Resolve-DnsName google.com -Server 192.168.1.1

This helps determine whether the problem is with the DNS server or your local configuration.

 

 

 5. Check DNS cache

• Get-DnsClientCache

This displays DNS records currently cached by the Windows DNS client.


To clear the cache:

• Clear-DnsClientCache

This is useful when troubleshooting situations where an old DNS record is being returned.

 

 

 

 6. Check whether a DNS server is reachable

You can test connectivity:

• Test-NetConnection 8.8.8.8 -Port 53

For your AD DNS server:

Test-NetConnection 192.168.1.10 -Port 53


Look for:

• TcpTestSucceeded : True

Important: DNS normally uses UDP 53, while Test-NetConnection -Port 53 tests TCP connectivity. So this is a connectivity check, not a complete DNS functionality test.

 

 

 7. Check the DNS client service

Windows has a DNS Client service.

• Get-Service -Name Dnscache

Example:


Status   Name       DisplayName
------   ----       -----------
Running  Dnscache   DNS Client


If necessary:

Restart-Service -Name Dnscache

Be careful with restarting services on production machines.

 

 

 

 A real IT Support troubleshooting scenario

Suppose a user says:

"I can connect to Wi-Fi, but I can't open websites."

Don't immediately assume it's an internet problem.

You could troubleshoot:

Step 1 — Check IP configuration

• Get-NetIPConfiguration

Step 2 — Check configured DNS

• Get-DnsClientServerAddress

Step 3 — Test DNS resolution

• Resolve-DnsName google.com

Step 4 — Test another DNS server

• Resolve-DnsName google.com -Server 8.8.8.8

Step 5 — Check DNS cache

• Get-DnsClientCache

Step 6 — Clear DNS cache if appropriate

• Clear-DnsClientCache

Then test again:

Resolve-DnsName google.com
For your Active Directory lab

This is particularly important for your System Engineer preparation.

Your lab should look roughly like:

 

On the Windows 10 client:

• Get-DnsClientServerAddress

Check that the DNS server points to your Domain Controller's IP, not an external DNS server such as 8.8.8.8.


Then:

• Resolve-DnsName yourdomain.local

And:

• Resolve-DnsName dc01.yourdomain.local

This is a much better lab exercise for your GitHub documentation because it demonstrates the relationship between DNS + Active Directory + Windows client troubleshooting, rather than simply showing individual commands.

Commands:

 

• Get-DnsClientServerAddress
• Get-DnsClientCache
• Resolve-DnsName
• Test-NetConnection
• Get-NetIPConfiguration
• Get-Service -Name Dnscache
• Clear-DnsClientCache